A wide variety of actuators and speakers are known. Applicant's co-pending applications, some of which are published as indicated above, describe state of the art actuators such as speakers.
The term bearing as used herein is intended to include any device which allows constrained relative motion, such as bending motion, between parts e.g. a device which connects a moving element to stationary elements and defines the path of motion and the at-rest position of the moving element. A flexure bearing or flexure is a bearing which allows bending motion. A flexure bearing may comprise a flexible part joining two other parts and is typically simple, inexpensive, compact and low friction. Flexure bearings are typically formed of a material which can be repeatedly flexed without disintegrating. A spring is intended to include any suitable elastic member such as but not limited to a spirally coiled strip or wire that recovers its shape after compression, bending or stretching. Addressing of an (i,j)'th actuator element in an array of actuator elements refers to application of voltage between a particular row and a particular column of the array of actuator elements.
An array is termed herein an “active” array if its elements include an element drive circuit, and is termed herein a “passive” array if its elements do not include an element drive circuit.
The terms ‘resting position’, ‘at-rest position’ and ‘at rest position’ are used generally equivalently in the present specification. The terms ‘actuator device’ and ‘actuating device’ are used generally equivalently in the present specification.
State of the art loudspeaker arrays and control algorithms useful therefor are described in the following publications by Malcolm Hawksford:
A. “Spatial Distribution Of Distortion And Spectrally Shaped Quantization Noise In Digital Micro-Array Loudspeakers”, J. Audio Engl Soc., Vol. 55, No. 1/2, 2007 January/February; and
B. Smart Digital Loudspeaker Arrays”, J. Audio Engl Soc., Vol. 51, No. 12, 2003 December.
It is appreciated that the terms “top” and “bottom” are used, when used, in the description or the drawings merely for convenience to indicate locations on either side of a surface defined by the array of moving elements such as the surface connecting the midpoints of the trajectories of the moving elements. Gravity, in many applications, is a negligible force such that a “top” location could equally well be disposed below or to the left or right of a “bottom” location.
The above terms may be construed either in accordance with any definition thereof appearing in the prior art literature or in accordance with the specification, or as above.
ANSYS Inc.'s Glossary of MEMS Terminology states that a dimple is “A small feature or bump, typically a raised square on the surface of a MEMS device. Dimples can be used as mechanical stops e.g. to control the touch down in a high aspect ratio device”.
The disclosures of all publications and patent documents mentioned in the specification, and of the publications and patent documents cited therein directly or indirectly, are hereby incorporated by reference.